Computer virtualization is a technique that involves encapsulating a physical computing machine platform into virtual machine(s) executing under control of virtualization software on a hardware computing platform or “host.” A virtual machine provides virtual hardware abstractions for processor, memory, storage, and the like to a guest operating system. The virtualization software, also referred to as a “hypervisor”, includes or more virtual machine monitors (VMMs) to manage the virtual machine(s). The virtualization software can execute various services that can be accessed locally on the host in order to initially configure the virtualization software. For example, an administrator can use a keyboard, mouse, and display of the host to interact with the console user interface service and perform local configuration of the virtualization software, such as configuration of network options. In another example, an administrator can use a keyboard, mouse, and display of the host to view logging information output by the virtualization software. Once local configuration is complete, an administrator can remotely access the virtualization software through a network interface using an application on a remote device.
Virtualization can also be provided on computing devices that have been configured to operate without a display, keyboard, mouse, and like type human interface devices, such as network appliances and the like. Such computing devices are referred to as being “headless.” In general, the virtualization software can provide access to services used for local configuration through an alternative channel, such as a serial port. For headless computing devices, the alternative channel can be the only available mechanism for locally configuring the virtualization software. Heretofore, a serial interface of the virtualization software is connected to a particular default service at boot and remains connected to that service until the host is rebooted. An administrator must interrupt the boot process manually or create a custom virtualization software image in order to change the service connected to the serial interface. Even in the case of a custom virtualization software image, if the administrator desires to change the service connected to the serial interface, the host must be rebooted and the administrator must manually interrupt the boot process.